Spear phishing is a technique used by spammers and scammers to try
to get your email username and password. They send you an email,
often claiming to be from your email provider or employer, in which
they say that your account will be deleted unless you supply them
with your username and password "for authentication" or some other
similar ruse. They say you must reply to the message giving them
this information, or send a message to a particular address giving
them this information.

ClamNailer takes 2 lists of addresses commonly used in these
attacks, and generates a ClamAV signature database to detect them.
